Full wave bridge check

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studiodunn
Posts: 293
Joined: Wed Nov 24, 2010 8:50 pm

Full wave bridge check

Post by studiodunn »

Can I get a sanity check on this full wave bridge. This is the first time I've built one and just wanted to hear that nothing looks odd. The first cap is lifted off the board for a better look in case that seems like something obvious I would need ;)

This is Peavey Classic conversion....I think the PT sockets are the only original part at this point.

Thanks in advance.
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Phil_S
Posts: 6048
Joined: Tue Oct 23, 2007 10:12 pm
Location: Baltimore, MD

Re: Full wave bridge check

Post by Phil_S »

Aside from using one more turret than required :lol: it looks OK to me. Have you applied power? What are the voltage readings a/c in and d/c out?

What is on that ground point? If that is the mains ground, don't put anything else there. Move it to what I think is the heater CT.
studiodunn
Posts: 293
Joined: Wed Nov 24, 2010 8:50 pm

Re: Full wave bridge check

Post by studiodunn »

I just love staking turrets so much😜 The absence of a ct made me rethink things after the fact.

I haven’t applied power yet, but it should be seeing 330 330 from the secondaries.

I’ll get the bias supply ground moved, thanks for the eyes.
Stevem
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Re: Full wave bridge check

Post by Stevem »

Yes the diodes are correct and if your still ordering parts I would get 4 .01 uf 600 volt rated ciramic disc caps to place in parallel with each diode which will cut down on switching noise getting in the low level audio chain.
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studiodunn
Posts: 293
Joined: Wed Nov 24, 2010 8:50 pm

Re: Full wave bridge check

Post by studiodunn »

Amp is up and running. It's ugly...like the ugliest wiring I've done to date. But hey, it's a freebie for a bandmate and it sounds pretty good.
Heyboer PT, salvaged skot OT from a Laney, a 4 herny choke from a70's bassman and any "close enough" parts i had on hand.
Pretty standard jcm800 layout with NFB knob - 437 on the plates -38 bias

One issue is the gain knob has a ugly range from 7 to 10. It almost sounds like blocking distortion but I'm not smart enough to understand how that would exist up to, but not at wide open.

She's a real looker!
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